1. Field of the Invention
The present invention relates to a functional elemental device formed by covering the surface of a conductive carbon material layer with an organic thin film, and an FET sensor using the same.
2. Description of the Prior Art
Conductive carbon material is recently noticed as a material having possibility of wide range development in the sensor, electronic device, electrochromy, electro-plating, photochemistry, optical conversion technology, semiconductor technology, and further, in fine processing technology, etc., by being joined with an organic thin film.
By the way, hitherto, the pattern of this conductive carbon material layer has been prepared by adhering conductive carbon such as a carbon paste on a substrate such as the gate of an FET, and by letting the product be subjected to heat solidification or the like.
However, it is extremely difficult to let these conductive carbon materials directly cover on the gate of an FET, and especially, to prepare in a state such that the pattern of the conductive carbon layer is separated from an insulating layer on a fine processing technology pattern (several hundred to several .mu.m order), and there was a limit in the size thereof.
Also, even in the case when the conductive carbon material is let directly cover the nitride film (Si.sub.3 N.sub.4 film) prepared by the dielectrics technology such as the vacuum deposition method, sputtering method, CVD (chemical vapor deposition) method of the recent thin film formation technology, there was the fear that the conductive carbon material layer peels off due to the difference of its thermal expansion coefficient with that of the nitride film. Also, there was such a problem that ions and easily displaceable substances, which are contained in the substrate of the insulating layer or the like such as described above, intrudes into the conductive carbon material layer, and the function as an element lowers.